This invention generally relates to techniques for wide area networking. More particularly, the present invention provides an apparatus for switching a plurality of optical signals using a novel optical configuration. Merely by way of example, the present invention is implemented using such apparatus in a wide area network for long haul telecommunications, but it would be recognized that the invention has a much broader range of applicability. The invention can be applied to other types of networks including local area networks, enterprise networks, and the like.
Digital telephone has progressed with the need for faster communication networks. Conventionally, standard analog voice telephone signals have been converted into digital signals. These signals can be 64,000 bits/second and greater in some applications. Other telephone circuits interleave these bit streams from 24 digitized phone lines into a single sequence of 1.5 Mbit/second, commonly called the T1 or DS1 rate. The T1 rate feeds into higher rates such as T2 and T3. A T4 may also be used. Single mode fiber optics have also been used at much higher speeds of data transfer. Here, optical switching networks have also been improved. An example of such optical switching standard is called the Synchronous Optical Network (SONET), which is a switching standard designed for telecommunications to use transmission capacity more efficiently than the conventional digital telephone hierarchy, which was noted above. SONET organizes data into 810-byte xe2x80x9cframesxe2x80x9d that include data on signal routing and designation as well as the signal itself. The frames can be switched individually without breaking the signal up into its components, but still require conventional switching devices.
Most of the conventional switching devices require the need to convert optical signals from a first source into electric signals for switching such optical signals over a communication network. Once the electric signals have been switched, they are converted back into optical signals for transmission over the network. As merely an example, a product called the SN 16000, BroadLeaf(trademark) Network Operating System (NOS), made by Sycamore Networks, Inc. uses such electrical switching technique. Numerous limitations exist with such conventional electrical switching technique. For example, such electrical switching often requires a lot of complex electronic devices, which make the device difficult to scale. Additionally, such electronic devices become prone to failure, thereby influencing reliability of the network. The switch is also slow and is only as fast as the electrical devices. Accordingly, techniques for switching optical signals using a purely optical technology have been proposed. Such technology can use a wave guide approach for switching optical signals. Unfortunately, such technology has been difficult to scale and to build commercial devices. Other companies have also been attempting to develop technologies for switching high number of signals in other manners, but have been generally unsuccessful.
From the above, it is seen that an improved way to switching a plurality of optical signal is highly desirable.
According to the present invention, a technique including an apparatus for optical switching is provided. More particularly, the invention provides an apparatus having a novel mirror configuration for switching one or more optical signals from a plurality of optical fibers from an input source to one of a plurality of output fiber ports.
In a specific embodiment, the present invention provides an apparatus for switching at least one of a plurality of optical signals from a plurality of optical fibers. The apparatus has an input fiber bundle housing comprising an outer side and an inner side. The input fiber bundle housing has a plurality of sites oriented in a spatial manner on the outer side for coupling to a plurality of input optical fibers. Each of the input optical fibers is capable of transmitting an optical signal. The apparatus also has a first mirror array disposed facing the inner side of the input fiber bundle housing. The first mirror array includes a plurality of mirrors. Each of the mirrors corresponds to one of the sites on the outer side of the input fiber bundle housing. A second mirror array is disposed facing the first mirror array. The second mirror array is also disposed around a periphery of the input fiber bundle housing. The second mirror array also has a plurality of mirrors, where each of the mirrors is capable of directing at least one signal from one of the mirrors on the first mirror array. The apparatus has an output fiber bundle housing comprising an outer side and an inner side. The output fiber bundle housing has a plurality of sites oriented in a spatial manner on the outer side for coupling to a plurality of output optical fibers. Each of the sites is capable of receiving at least one signal from one of the second mirrors.
In an alternative embodiment, the apparatus has a novel switching apparatus. The apparatus switches one of a plurality of optical signals from a plurality of optical fibers. The apparatus has a top side comprising a top fiber bundle housing and a top mirror housing disposed around a periphery of the top fiber bundle housing. The apparatus also has a bottom side coupled to the top side. The bottom side is substantially facing the top side. The bottom side is a substantially parallel to the top side. The bottom side comprises a bottom mirror housing and a bottom fiber bundle housing disposed around a periphery of the bottom mirror housing.
Many benefits are achieved by way of the present invention over conventional techniques. In some embodiments, the invention provides a novel coaxial configuration where, for example, reflection angles are reduced, thereby providing for more effective switching of signals. The invention configuration with near normal angle of incidence reduces polarization induced losses in still further embodiments. In other embodiments, the invention provides for a more efficient and smaller form factor, which allows the apparatus to be implemented in smaller spatial regions. The invention can also provide a configuration for easier alignment between the fiber bundle and mirrors in some embodiments. Here, the novel coaxial configuration allows for easier assembly and alignment between the mirrors and fiber bundle. The invention can also provide a smaller spot size for the signal due to the near normal incident optical signal, thereby allowing one to use smaller mirrors than would be required in conventional techniques. This could result in larger port count switch versions as compared to conventional techniques. The invention also has a less demanding requirement for deflection of the mirrors in the array in other embodiments. Depending upon the embodiment, one or more of these benefits may be achieved. These and other benefits will be described in more throughout the present specification and more particularly below.